For low cost fabrication and assembly of many electronic/electrical products, it is necessary to establish an efficient mechanized method of joining electronic components onto printed wiring boards and other workpieces. Currently, there exist mechanized systems to apply electrical hardware components such as pin terminals, tabs, sockets, etc. to their appropriate workpieces. But many other components continue to rely on manual assembly. For example, the machine disclosed in U.S. Pat. No. 4,318,964 provides an apparatus with a supply strip for inserting terminals into a substrate or workpiece. The supply strip is a continuous strip of metal pins wound on a reel. To insert a pin into a printed wiring board (PWB), a pin is separated from the rest of the strip, then pressed down into the PWB. Another machine of this type is described in U.S. Pat. No. 4,807,357.
The current systems are used for assembling of pins or tabs or sockets into substrates. The pin insertion machines allow for insertion of different sizes of pins onto an apertured workpiece. The pins can vary in cross section and length. They can also be bent to 90.degree. angles or kept straight. The machine is fed from a continuous supply of prenotched pins wound on a reel. The pins are fed, cut, formed and then inserted into the workpiece positioned below the inserter. The alignment of the insertion hole with the pin can be achieved by manually positioning the workpiece below the insertion head, or automatically by a computer-controlled X-Y locating table onto which PWB's are loaded. A similar type of machine can be used to insert sockets, or tabs or other components into PWB's. Any socket pattern can be machine inserted or can be inserted into a plastic housing for manual insertion. The above systems describe production systems to insert pins or sockets into substrates. It is accomplished by inserting one pin or one socket or one tab at a time.
Other prior art includes a system that inserts many pins, up to as many as 50 at one time. The idea is similar to the previous system in that a continuous supply of header mounted pin components are stored and fed from a reel. The difference is that the pins are first perpendicularly inserted into an extruded plastic header which is then stored on the supply reel. The endless electrical connector described in U.S. Pat. No. 4,832,622 is an example of one such system. A machine automatically cuts a header with a desired, pre-set amount of pins from the supply reel. An inserter head then places the header onto a PWB. While this system increases the efficiencies of some of automated component assembly, it is still not fully automated for other hardware components. Three examples follow which illustrate (and not limit) those components which up until now have resisted mechanized assembly.
One example of a electrical component that is currently being made individually and manually assembled is an electrical shunt connector or jumper, which is in common use today to interconnect pins to configure, for example, a printed circuit board. The plastic body of the shunt is currently individually molded, and a stamped metal conductor is inserted into the plastic body and then the completed shunt assembly is manually mounted on the PWB pins, using templates or light to properly locate the pins on which the shunt is to be assembled. The process is labor intensive, expensive and causes re-work of boards if the shunt is improperly positioned.
Another example and an important electronic component is wire end terminals. Their assembly onto wires has not been automated yet. The end terminal needs to be placed on the wire and is done so manually and individually. There is no known system that allows for the mechanized assembly of such components.
Another example is in situations where the system has inserted long rows of male metal connector pins into a PWB. Problems arise when the female connector then has to be mated. For instance, when the connector is being mated the pins might bend if the assembly is not done evenly along the axis of the pins. The problem is exacerbated when connectors are used with high pin counts. Typically, the problem of the bent pins is solved with a shrouded header that has an integrally molded pilot at either end of the header. The female connector first mates with the pilot (which is higher than the pins) and this assures that the axis of the pins and that of the connectors are properly aligned. But, the shrouded header with its integrally molded pilot is expensive, and it takes time to configure and assemble for a particular connector.
Among the common disadvantages in the assembly of the three component examples described above are the high cost and that individual handling of loose pieces are still required in the manufacture or assembly process. This is time consuming and costly. Furthermore, the expense of ordering and storing loose electronic parts is high. While the problem is particularly acute with the above described three components, there are other components whose manufacture and assembly involve similar problems.